1) An organism with specific nutritional requirements. 2) A nutritional mutant which can grow on the minimal medium meant for a prototroph only when it has been provided with extra metabolites which the mutant cannot now synthesize. Different types of auxotrophs give rise to an occasional prototroph when grown together( due to recombination)….

List of Biology Words Starting with A

…m autonomous replication sequence (ARS) autonomous specification autopolyploid autoradiography autoregulation autosomal dominant autosomal recessive autosomal set autosome autotroph autozygosity autozygous auxin auxotroph auxotrophic mutant average average molecular weight avidity Avogadro’s law Avogadro’s number (N) Avuncular relationship axial skeleton axil axilla axon axoneme azoic…

selective mutation

A change in a gene that is specifically selected. Example: An adenine-requiring auxotroph yeast strain is grown on an adenine-containing media plate. Then a large number of cells from the strain is then plated on media containing no adenine (minimal medium). The only cells that can grow and divide on this medium are adenine prototrophs, which must have arisen by reverse mutation in the original culture….


A strain of organisms that will proliferate on minimal medium (compare auxotroph)….

leaky mutant

A mutant (typically an auxotroph) that results from a partial rather than a complete inactivation of the wild-type function….